dan.thoughts

Few times i needed to build dynamic-settings support into the application, which means that users (admins) can redefine website parameters like html keywords, notification email adresses and other simple data, that cannot be put into application environment settings. So, i extracted a small helper that will give me such ability across multiple apps – AppConfig

AppConfig is a library to manage your (web) application dynamic settings with flexible access and configuration strategy. Primary datasource for AppConfig is an ActiveRecord model.

Installation

git clone git://github.com/sosedoff/app-config.git
cd app-config
gem build
gem install app-config-x.y.z.gem

Data Formats

You can use following formats:

• String
• Boolean
• Array
• Hash

String format is a default format. Everything is a string by default.

Boolean format is just a flag, values ‘true’, ‘on’, ‘yes’, ‘y’, ‘1’ are equal to True. Everything else is False.

Array format is a multiline text which is transformed into array. Each evelemnt will be trimmed. Empty strings are ignored.

Hash format is special key-value string, “foo: bar, user: username”, which is transformed into Hash instance. Only format “keyname: value, keyname2: value2″ is supported. No nested hashes allowed.

Usage

AppConfig is designed to work with ActiveRecord model. Only ActiveRecord >= 3.0.0 is supported.
By default model “Setting” will be used as a data source.

Here is default structure:

ActiveRecord::Schema.define do
  create_table :settings do |t|
    t.string :keyname
    t.string :value
    t.string :value_format
  end
end

Now, configure:

AppConfig.configure

If your settings model has a different schema, you can redefine columns:

AppConfig.configure(
  :model  => Setting,           # define your model as a source
  :key    => 'KEYNAME_FIELD',   # field that contains name
  :format => 'FORMAT_FIELD',    # field that contains key format
  :value  => 'VALUE_FIELD',     #field that contains value data
)

Load all settings somewhere in your application. In Rails it should be initializer file.

AppConfig.load

AppConfig gives you 2 ways to access variables:

AppConfig.my_setting      # method-like
AppConfig[:my_setting]    # hash-like by symbol key
AppConfig['my_setting']   # hash-like by string key

You can define settings items manually. NOTE: THESE KEYS WILL BE REMOVED ON RELOAD/LOAD.

AppConfig.set('KEYNAME, 'VALUE', 'FORMAT')

Everytime you change your settings on the fly, use reload:

AppConfig.reload

Cleanup everything:

AppConfig.flush

Github source: https://github.com/sosedoff/app-config